The state would have to pull off a $6-billion feat in 5 years or risk losing federal funds for the bullet train.

If California starts building a 130-mile segment of high-speed rail late this year as planned, it will enter into a risky race against a deadline set up under federal law.

The bullet train track through the Central Valley would cost $6 billion and have to be completed by September 2017, or else potentially lose some of its federal funding. It would mean spending as much as $3.5 million every calendar day, holidays and weekends included -- the fastest rate of transportation construction known in U.S. history, according to industry and academic experts.

Over four years, the California High-Speed Rail Authority would need as many as 120 permits, mostly from a tangle of government regulatory agencies not known to rush their business. It would need to acquire about 1,100 parcels of land, many from powerful agriculture interests that have already threatened to sue. And it would need to assemble five teams of contractors with giant workforces positioned from Fresno to Bakersfield, moving millions of tons of gravel, steel rail and heavy equipment across the valley.

Even if the authority avoids any delays, its ability to complete the first construction section on time will require a breakneck pace of activity.

For The Record Los Angeles Times Tuesday, May 22, 2012 Home Edition Main News Part A Page 4 News Desk 1 inches; 41 words Type of Material: Correction Bullet train: In an article in the May 14 Section A and another in the May 16 LATExtra section about construction costs for the California bullet train, the last name of Parsons Brinckerhoff construction expert John Popoff was misspelled as Popov.

"It is a very aggressive plan," said Manuel Garcia, associate director at the Construction Industry Institute affiliated with the University of Texas at Austin. "It does appear that it will be a challenge."

If the rail authority runs into technical problems, legal disputes, permit delays or political roadblocks, it could end up building less track and potentially leave an uncompleted project, according to warnings contained in its own business plan. If the project blows past the federal deadline, for example, the flow of money could be stopped. And the scramble to meet that deadline could lead to construction problems and drive up costs.

Rail officials acknowledge that their plans are aggressive but describe them as not unprecedented, pointing to the fast construction pace of the new Bay Bridge in Oakland and the Alameda Corridor freight rail line in Los Angeles.

But state reports show the $6.5-billion Bay Bridge will have an average spending pace, or "burn rate," of $1.8 million per day when it is completed in 2013, less than half what the rail authority is planning. The Alameda Corridor had a similar $1.8-million-per-day burn rate by its completion in April 2002, much less than planned for the bullet train even when adjusted for inflation.

The hurried project to improve I-15 in Salt Lake City before the 2002 Olympics, known in the construction industry as one of the fastest well-executed work packages, spent $1.6 million per day, according to John Njord, executive director of the Utah Department of Transportation.

"That was a burn rate like we have never seen before," he said, which was on schedule only because of careful planning. The California effort would more than double that pace.

John Popov, a construction expert at Parsons Brinckerhoff, a consulting firm working with the rail authority, said he believes the project can be completed on time.

Popov calculates that the job will spend $2.7 million per day, which excludes the cost of land acquisition, environmental work, management oversight and reserves. Construction experts say that including all of its costs, the authority would spend $3.5 million per day. Popov added that the authority is considering whether it can legally shift as much as $1.3 billion of work past the 2017 deadline, an option that has not been vetted with the Legislature.

Outside experts say that only careful management like that in the Utah job can ensure that the Central Valley rail plan does not go haywire. The rail authority has just 37 employees and has been operating for months without a chief executive, a deputy chief executive or a chief financial officer. It also has no single executive overseeing construction, which outside consultants say is needed.

"You have 37 mere mortals who have never done anything like this before," said Robert Bea, a member of the National Academy of Engineering, a retired UC Berkeley professor of civil engineering and director of the National Science Foundation's project on California's transportation infrastructure. "They need God, because he's the only one who can handle this management challenge."

A final environmental report on about half of the 130-mile project is uncompleted and months behind schedule, forcing the agency to start work initially on a 29-mile section from Madera to Fresno and hope that it can get the review problems with the rest of the line cleared up later this year.